Method and apparatus for controlling combustion quality of a gaseous-fuelled internal combustion engine
First Claim
1. A method of operating a gaseous-fuelled internal combustion engine, said method comprising:
- (a) determining a target heat release rate (HRR) for a current cycle of said internal combustion engine;
(b) comparing characteristics of said target HRR to selected characteristics of a trace indicative of an actual HRR for said cycle determined from a previous cycle of said internal combustion engine;
(c) during said cycle of said internal combustion engine;
(i) directing an intake charge into said combustion chamber defined in said engine;
(ii) compressing said intake charge within said combustion chamber;
(iii) introducing at least one gaseous fuel into said combustion chamber;
(iv) introducing a quantity of a pilot fuel into said combustion chamber at a pilot fuel timing, said pilot fuel capable of auto-igniting at a first crank angle when a piston is near or at top dead center within said combustion chamber near completion of a compression stroke during said cycle, said combustion chamber partially defined by said piston;
(v) actuating an HRR control lever to reduce differences between said characteristics of said trace and said characteristics of said target HRR, said HRR control lever comprising at least one of said pilot fuel timing and said quantity of said pilot fuel;
(vi) burning said gaseous fuel and said pilot fuel, said gaseous fuel ignited as a result of combustion of said pilot fuel.
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Abstract
A method and apparatus for controlling to a target heat release rate (HRR) uses an HRR control lever, namely, pilot fuel timing and/or pilot fuel quantity, used in a gaseous-fuelled compression ignition internal combustion engine. The mechanism to control HRR to a target HRR improves engine performance and emissions. A target HRR is determined for a cycle of an engine. An HRR control lever is then used to adjust to the target HRR in consideration of combustion conditions in the engine and the difference between the target HRR and cycle HRR predicted for the cycle by reference to, by way of example, a derived HRR trace from a previous cycle, a pressure trace, a measured property of the exhaust gas directly determined or mapped values provided during calibration allowing for adjustment to a target HRR for the engine. The mapped values can be cross-referenced to engine combustion conditions.
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Citations
34 Claims
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1. A method of operating a gaseous-fuelled internal combustion engine, said method comprising:
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(a) determining a target heat release rate (HRR) for a current cycle of said internal combustion engine; (b) comparing characteristics of said target HRR to selected characteristics of a trace indicative of an actual HRR for said cycle determined from a previous cycle of said internal combustion engine; (c) during said cycle of said internal combustion engine; (i) directing an intake charge into said combustion chamber defined in said engine; (ii) compressing said intake charge within said combustion chamber; (iii) introducing at least one gaseous fuel into said combustion chamber; (iv) introducing a quantity of a pilot fuel into said combustion chamber at a pilot fuel timing, said pilot fuel capable of auto-igniting at a first crank angle when a piston is near or at top dead center within said combustion chamber near completion of a compression stroke during said cycle, said combustion chamber partially defined by said piston; (v) actuating an HRR control lever to reduce differences between said characteristics of said trace and said characteristics of said target HRR, said HRR control lever comprising at least one of said pilot fuel timing and said quantity of said pilot fuel; (vi) burning said gaseous fuel and said pilot fuel, said gaseous fuel ignited as a result of combustion of said pilot fuel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A control apparatus for controlling heat release rate (HRR) in a gaseous-fuelled direct injection internal combustion engine, said control apparatus comprising:
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(a) a controller; (b) at least one sensor for monitoring a signal, said at least one sensor in communication with a controller capable of processing said signal to provide a trace indicative of an actual HRR; (c) an HRR control lever, in communication with said controller, said controller capable of adjusting said HRR control lever in response to a difference between said trace and a target HRR. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification